The Distributive Property of Multiplication

Grade 4 GLE 17

Recall the distributive property of multiplication over addition . . .

symbolically:

a × (b + c) = a × b + a × cand pictorially (rectangular array area model):

a × b a × ca

b c

An example: 6 x 13 using your mental math skills . . .

symbolically:

6 × (10 + 3) = 6 × 10 + 6 × 3and pictorially (rectangular array area model):

6 × 10 6 × 36

10 3

What about 12 x 23? Mental math skills?

(10+2)(20+3) = 10×20 + 10×3 + 2×20 + 2×3

10 × 20 10 × 310

20 3

2 × 32 2 × 20

200

30

40

+ 6

276